Abstract
A B S T R A C T Hearing loss (HL) is one of the most common sensory defects, affecting approximately 1 in 1,000 newborns worldwide, while nearly 4% of individuals under 45 years of age experience some degree of hearing impairment, with a significant genetic contribution. Non-syndromic hearing loss (NSHL) is predominantly inherited in an autosomal recessive manner (75–80%), followed by autosomal dominant inheritance (20–25%), with X-linked and mitochondrial patterns accounting for a small proportion of cases (1–2%). The DeaFNess, autosomal recessive, locus B1 (DFNB1) is a major genetic contributor to autosomal recessive non-syndromic hearing loss (ARNSHL) globally. Two deletions in the Gap Junction Protein Beta 6 gene (GJB6), del(D13S1830) and del(D13S1854), are commonly implicated in this locus. The present study aimed to investigate the contribution of GJB6 deletions to hearing loss in four unrelated Libyan families. A total of 38 participants were involved, including 17 individuals diagnosed with congenital NSHL and 21 unaffected relatives from the same families. Following DNA extraction from blood samples, multiplex polymerase chain reaction (PCR) was performed, and the amplified products were visualized by agarose gel electrophoresis. Selected products were further analyzed by DNA sequencing. Neither the del(D13S1830) nor the del(D13S1854) GJB6 deletions were detected in any of the examined samples. However, DNA sequencing identified a heterozygous C/T variant in the GJB6 gene in one family, suggesting the presence of a rare or potentially novel variant associated with NSHL. The absence of these deletions in the studied families indicates that genetic factors other than GJB6 may play a role in the etiology of ARNSHL in the Libyan population. These findings highlight the genetic heterogeneity of NSHL and emphasize the need for further comprehensive genetic investigations to elucidate the full spectrum of causative genes in this population.